A liquid crystal display apparatus is widely applied to a display device due to advantages of low power consumption, long lifetime, environmental protection and the like. However, because a liquid crystal panel in the liquid crystal display apparatus does not have light emitting characteristic itself, it is needed to provide a surface light source apparatus to the liquid crystal panel, such as a backlight source, in order to enable the liquid crystal panel to display an image. The backlight source serves to provide a surface light source with uniform brightness to the liquid crystal panel, thereby enabling the liquid crystal panel to achieve the objective for displaying an image.
In an existing backlight source, a light emitting component generally employs a light emitting diode (hereinafter referred to as a LED) light source, wherein advantages of low working voltage, high light emitting brightness, high response speed, long lifetime and the like of the LED light source are mainly utilized. However, because the exit light of the LED light source has a relatively strong optical directivity, that is, the exit light has a certain divergence angle, when the exit light of the LED light source directly enters the light guide plate from a light entrance surface of the light guide plate, an optical dark region will appear on a light exit surface of the light guide plate. Particularly, with reference to FIG. 1 and FIG. 2, after light emitted out from each first light source 20 is incident on a light entrance surface 11 of a light guide plate main body 10, an optical dark region (a zone shown by a section line in drawings) will appear on one side, which is close to the light entrance surface 11, of a light exit surface 12. The optical dark region is mainly distributed between two adjacent first light sources 20, thereby causing a non-uniform light emitted out from the light exit surface 12, which seriously affects the exit light uniformity of the backlight source.